The present disclosure relates to a method for mutually connecting substrates having a plurality of electrodes formed thereon, and a flip chip mounting body and a mutual connection structure between substrates formed by using the same.
In recent years, along with an increase in the density of semiconductor integrated circuits (LSIs), circuit substrates and electronic components used in electronic equipment, the pin count of the electrodes is increasing and the pitch thereof is decreasing rapidly. With methods for mounting these electronic components, there are demands for accommodating narrower pitches, realizing shorter tact times, enabling a single-step formation of connectors, etc.
With these demands, some inventors of the present application have proposed, in WO 2006/103948 A1 (US 2008/0284046 A1), a flip chip mounting method, which uses a resin containing conductive particles and a gas bubble generating agent, as a next-generation mounting method.
FIGS. 11A to 11D are cross-sectional views showing basic steps of the flip chip mounting method disclosed in the above-mentioned document.
As shown in FIG. 11A, a resin 11D containing conductive particles 111 and a gas bubble generating agent (not shown) is supplied onto a circuit substrate 130 having a plurality of connection terminals 131 thereon. Then, as shown in FIG. 11B, a semiconductor chip 132 having a plurality of electrode terminals 133 thereon is placed so as to face the circuit substrate 130. Then, as shown in FIG. 11C, the resin 110 is heated so as to generate gas bubbles 114 from the gas bubble generating agent in the resin 110. In this process, the resin 110 is pushed by the growing gas bubbles 114 toward the outside of the gas bubbles 114, whereby the resin 110 is self-assembled between the connection terminals 131 and the electrode terminals 133. Then, as shown in FIG. 11D, the resin 110 is further heated so as to melt the conductive particles 111 in the resin 110, which have been self-assembled between the connection terminals 131 and the electrode terminals 133 (hereinafter referred to simply as “between terminals”), thereby forming connectors 113 between terminals. Thus, there is obtained a flip chip mounting body in which terminals are electrically connected together via the connectors 113 therebetween. Note that this method can also be applied to, for example, the connection between substrates having electronic components mounted thereon.